1 Field of the Invention
The present invention relates to switches and, more specifically, to vehicle steering column mounted switches for controlling vehicle operating circuits and components.
2 State of the Art
The evolution of steering column switches in motor vehicles has been toward greater integration of functions in a single switch lever. Previously, a plurality of individual switches, each controlling a single vehicle function, i.e., turnsignals, windshield wipers, headlights, etc., were mounted on the vehicle dashboard. Current steering column switch levers are designed to control a variety of functions for vehicle operating circuits or devices, such as turnsignals and hazard lights, high beam and low beam headlights with optional flash-to-pass, parking lights, fog lights, windshield wiper and wash functions, including multi-speed wipers with or without intermittent delay.
Typically, a steering column stalk switch includes a single lever or stalk pivotally mounted on one side of a housing attached to the vehicle steering column in an easily accessible position for access by the driver of the vehicle. The lever is gimballed at one end in housing so as to move in one and, typically, two mutually separate planes. Further, the lever may be provided with a rotatable end cap, and/or a slidable member movable along the longitudinal axis of the lever to control additional vehicle operating circuits. An intermediate member on the lever may also be rotatable to control another vehicle circuit or device. Actuators are mounted in the housing and, in response to movement of the lever in different directions or planes, rotation of the end cap, or movement of the slidable member, or rotation of the intermediate member on the lever, move a switching member carrying contacts between various switching positions to effect the switching of electrical connections for a particular vehicle operating circuit.
In some vehicles, particularly vehicles manufactured in Europe and/or Japan, two steering column stalk switches are provided, one mounted on the left side of the steering column and one on the right side of the steering column. The various vehicle operating circuits or devices described above are split between the two stalk switches, with the left stalk switch typically controlling vehicle headlight, parking light, fog light, flash-to-pass operation as well as turnsignal operations. The right mounted stalk lever typically controls windshield wiper, mist and wash devices.
However, regardless of whether one or two stalk switches are employed in a vehicle, vehicle design constraints require that the stalk switch lever and the housing assembly be as small as possible while at the same time providing easy access to and movement of the various switches on the stalk switch(es). At the same time, each stalk switch must meet further design constraints relating to a low manufacturing cost, a minimal number of individual components, ease of assembly, and ease of installation in the vehicle. Such stalk switches must also have the capability of easy modification to different vehicle design parameters, such as the ability to control when the vehicle fog lights are operable with respect to the state of the vehicle high beam or low beam headlights. It would also be desirable to provide a vehicle mounted steering column stalk switch which is capable of three modes or degrees of motion, namely, radially, axial and gear driven to operate a plurality of electrical circuits in the vehicle. It would also be desirable to provide a vehicle mounted steering column stalk switch which has the capability of operating a plurality of auxiliary circuits in a single stalk switch lever.
A vehicle steering column stalk switch apparatus constructed in accordance with the present invention includes a unique fog lamp interlock switch which limits the ability of a vehicle operator to switch on the vehicle front and/or rear fog lamps to only certain operative states of the vehicle headlamps.
In one aspect of the invention, a housing is mounted on a vehicle steering column and has a lever mounted thereon. A first contractor is mounted in the housing for movement between distinct positions and carries contacts electrically connectable to conductive elements in the housing which are connected to a first set of vehicle operating circuits.
A first actuator is rotatably mounted on the lever for movement independent of the lever. A second contractor is mounted in the housing and is selectively movable into contact with conductive elements carried in the housing for controlling operation of a second vehicle operating circuit. Means cooperate between the first actuator and the second contractor for permitting movement of the second contractor from a first position to a second position only in predetermined positions of the first actuator. In the second position, the second contractor engages contacts with selected conductive elements or traces in the housing to turn on the second vehicle operating circuit.
In one preferred aspect, the first actuator is in the form of an end cap movably coupled to the lever for rotation with respect to the lever. A shaft extends through the lever and has a first end fixed to the end cap and an opposed second end engagably coupled to the first contractor for controlling the first set of vehicle operating circuits such that rotation of the end cap and the shaft causes movement of the first contractor between positions.
A cam is formed in the lever and defines the rotated positions of the actuator where the actuator is allowed to move to the second position. A cam follower is carried on the shaft and movable along the cam. The cam is formed to allow axial translation of the end cap with respect to the lever only in certain rotated positions of the end cap with respect to the lever.
Different cams may provided which allow the end cap to be linearly movable relative to the lever when the end cap has been rotated to a first position in which the first actuator and first contractor complete a circuit to turn the vehicle park lights on, and/or to a second position in which the end cap is rotated to a position in which the first actuator and first contractor complete a electrical circuit to turn on the vehicle low beam and/or high beam headlamps.
The cam may also provide for separate actuation of rear vehicle fog lamps only after front mounted vehicle fog lamps have been activated by further rotation of the end cap from its translated position with respect to the lever.
According to one aspect of the present invention, all of the electrical contacts necessary to open and close circuits controlling the state of the operating circuits for the vehicle headlamps as well as the vehicle fog lamps, for example, are mounted on a single contractor which is moved between separate positions opening and closing various electrical circuits in response to rotation of the end cap relative to the lever as well as linear translation of the end cap with respect to the lever as described above.
According to another aspect of the present invention, a detent surface with a plurality of discrete detents is formed in a tubular member mounted about the shaft concentric within the lever. The cam follower is in the form of a plunger mounted on the shaft and rotatably engagable with the detents to define the distinct rotated positions of the end cap relative to the lever.
The detents extend axially on an inner surface of the tubular member. A radially inward step is formed in each detent surface to provide tactile feel for axial translation of the end cap relative to the lever.
The plunger also acts as the cam follower and rides along the cam to define the axially translated positions of the end cap relative to certain rotated positions of the end cap or actuator.
The present vehicle fog lamp interlock switch mountable in a vehicle steering column stalk switch lever uniquely provides a steering column switch apparatus with the capability to switch a moving contractor which is driven by rotation of an actuator mounted on a lever through a first group of operative states opening and closing electrical circuits via connection of an electrical contact on the contractor with conductive traces on the substrate to additionally open and close a separate circuit via a separate contact carried on the contractor through a separate movement of the actuator with respect to the lever. This provides multiple functions on a single vehicle stalk switch lever thereby affording the advantages of a small compact lever, simplified installation due to the combination of multiple control devices in a single lever, as well as a lower manufacturing cost due to the use of a reduced number of separate components.